<template>
  <div id="app" ref="bar">
    <button @click="add" ref="list">222</button>
    <router-view/>
  </div>
</template>

<script>
  export default {
    methods: {
      add() {
        this.$refs.list.style="color:red"
      }
    },
  }
</script>

<style lang="scss">
*{
  margin: 0;
  padding: 0;
}
// #app,html,body{
//   height: 100%;
// }
</style>
